I'm a bit late to this thread...
However, I at least have an excuse! My B&W P7 Wireless headphones I've been rocking for many, many years without issues, and they've been AMAZING.
But recently, the metal "connector" piece on the main headband had been coming slightly loose from where it fits into the headphone speaker unit itself (RHS).
The issue was caused by a small pin inside the headphone that stops this connector from coming loose (see arrow):
Of course, i naively simply pushed it back in and jogged on. However, over time, this policy led to a final cut in one of the wires and bang...suddenly when on bluetooth, no audio going into the LHS. No option but to open the beggar up, and continuity testing confirmed a break in one of the wires carrying audio from the RHS to LHS (when attached to the headphone cable rather than wireless, no audio loss was detected in either speaker).
I was not able to locate the precise position of the cable cut, and so i (perhaps unwisely?!) desoldered the wire from both headphones and decided to just replace it. This seemed to be the easier option at that time. Ha!
But I'm having a tricky time getting replacement wire. It appears to be 5-core shielded audio cable. I can get a product called Tasker C181—it's 3 mm in diameter. Or UL2547...which is is 3.5 mm diam. However, the original B&W wire seems to be only 2 mm diam, and any more than that may have issues feeding through the various holes...
Which is an issue of perhaps gargantuan proportions! I've just tried to feed the original wire through the small hole in the metal piece that feeds into the speaker cup...and I just don't see how B&W have done it...it essentially is a 90-degree angle...and, furthermore, the hole in the headband wire is now blocked by the old wire because I was not able to feed it the entire way through without it getting stuck (!!)...
So I'm wondering how to proceed. Unless I can find some 2 mm 5-core wire, I'm unlikely to be able to get it "as new" visually. Even if I can locate such thin wire, I currently cannot imagine how to feed it though that 90-degree turn, and then how to remove the stuck wire inside the headband (strong vacuum or a coathanger?!).
Maybe I will need to just go with a major bodge job, and proceed with the thicker wire, accepting that I may have to open up a hole in the side of the headphone cups and also just sticking the wire to the top of the headband instead. Not great visually, but all I really am mainly interested in is bringing these amazing headphones back to life so that they sound as they did. After all, you can't see yourself while you're wearing them, so who cares anyway?!
Any thoughts greatly appreciated!
Oh, and to the previous post r.e. the battery—it's not a difficult job at all...inside the (left?) cup and only 3 wires to desolder, if you have the gear.